The invention relates to a sealing mechanism for a double-lid system allowing a contamination-free transfer of radioactive or toxic substances from one container to another.
A double-lid system of this type is presented and described in German Pat. No. 20 47 538. As shown therein, a drum is initially pressed against the chamber flange in such a manner that simultaneously the flange-type seal of the drum is engaged with the flange of the chamber and the outer rim of the drum lid is engaged with the chamber lid seal. The drum lid and the chamber lid are then coupled together and the locking mechanism of the drum lid is released. The chamber lid and drum lid can then be lifted as a unit and brought into the chamber, allowing the transfer of substances from the chamber to the drum or vice versa. After completion of the transfer, the chamber and drum are both sealed and the chamber lid and drum lid are separated from each other. The purpose of this system is, above all, to prevent the chamber and drum lid outer surfaces, which are exposed to the atmosphere, from becoming contaminated in the process. Thus, the chamber seal and the drum seal must each carry out two different functions. Their radially outer regions should be engaged with the inner and outer surfaces, respectively, of the chamber flange; at the same time, their radially inner regions should hold the rim of the drum lid firmly between them. Problems, due, for example, to tolerances, may arise however. If the rim of the drum lid is somewhat too thick, the chamber flange seal will be impaired; if it is somewhat too thin, it will not be pressed against the seals sufficiently and will not seal properly.
The object of the invention is to improve the sealing machine of this kind of double-lid system in such a way that the chamber lid seal and the drum seal fully retain their sealing capability with respect to both the chamber flange and the rim of the drum lid during all operations, in spite of the occurrence of geometric or material deviations (tolerances) of the interacting parts.